U.S. Pat. No. 7,011,196, hereby incorporated by reference herein, describes a hydraulic torque converter with a bridging clutch.
In FIG. 1, a prior art torque converter 10 contains a cover 12, an impeller 14, a turbine 16, and a bridging clutch 18. Torque converter 10 is driven by an engine connected at hole 20. Cover 12 has a front cover 22 and a back cover 24, secured and sealed together, for example welded. Impeller 14 is rigidly attached to back cover 24. Turbine 16 is rigidly attached to a turbine hub 26 with, for example, rivets 28. Turbine hub 26 is non-rotatably attached to a shaft 30 with, for example, splines 32. Shaft 30 may be the input shaft of a transmission, for example.
Leaf springs have been known to connect the piston of bridging clutch 18 to a separate piece later welded to front cover 22. Alternately, the piston, which can be in the form of a plate, splines to front cover 22 which can cause a rattle or noise complaint. Another method is to attach the piston to front cover 22 with leaf springs, typically positioned radially outside of friction surfaces.